In vivo EMG biofeedback in violin and viola pedagogy

In vivo EMG biofeedback was found to be an effective pedagogical tool for removing unwanted left-hand tension in nine violin and viola players. Improvement occurred rapidly and persisted throughout a 5-month follow-up period. Further studies will be necessary to assess the effect of biofeedback independent of placebo effects. The brevity of the method and the magnitude of improvement warrant further investigation.     

Metal ion stabilization of the conformation of a recombinant 19-kDa catalytic fragment of human fibroblast collagenase.

A recombinant 19-kDa human fibroblast collagenase catalytic fragment modeled on a naturally occurring proteolytic product was purified from E. coli inclusion bodies. Following renaturation in the presence of zinc and calcium, the fragment demonstrated catalytic activity with the same primary sequence specificity against small synthetic substrates as the full-length collagenase. Unlike the parent enzyme, it rapidly cleaved casein and gelatin but not native type I collagen. Intrinsic fluorescence of the three tryptophan residues was used to monitor the conformational state of the enzyme, which underwent a 24-nm red shift in emission upon denaturation accompanied by quenching of the fluorescence and loss of catalytic activity. Low concentrations of denaturant unfolded the fragment while the full-length enzyme displayed a shallow extended denaturation curve. Calcium remarkably stabilized the 19-kDa fragment, zinc less so, while together they were synergistically stabilizing. Among divalent cations, calcium was the most effective stabilizer, EC50 approximately 60 microM, and similar amounts were required for substrate hydrolysis. Catalytic activity was more sensitive to denaturation than was tryptophan fluorescence. Least sensitive was the polypeptide backbone secondary structure assessed by CD. These observations suggest that the folding of the 19-kDa collagenase fragment is a multistep process stabilized by calcium.     

Desensitization of the Neurokinin 1 Receptor Is Mediated by the Receptor Carboxy-Terminal Region, but Is Not Caused by Receptor Internalization

Abstract: The carboxy-terminal cytoplasmic regions of the rat neurokinin 1 (substance P) and neurokinin 2 (neurokinin A) receptors have been exchanged to determine if this region of the neurokinin 1 receptor is involved in its desensitization. When expressed at similar levels in stably transfected Chinese hamster ovary (CHO) cell lines, receptors containing the carboxy-terminal region of the neurokinin 1 receptor desensitized significantly more (as measured by reduction of the inositol 1,4,5-trisphosphate response) when preexposed for 1 min to 1 µ M neurokinin, indicating a role for the carboxy-terminal region of the neurokinin 1 receptor in its desensitization. Measurement of receptor internalization using radiolabeled neurokinins (0.3 n M ) indicated that ∼75–80% of the receptors were internalized in each cell line after 10 min at 37°C, with no observable correlation between neurokinin receptor desensitization and internalization. Measurement of loss of receptor surface sites for cell lines CHO NK1 and CHO NK1NK2 following exposure to 1 µ M substance P also indicated no obvious relationship between the percent desensitization and percent of receptors internalized. Also, two inhibitors of neurokinin 1 receptor internalization, phenylarsine oxide and hyperosmolar sucrose, did not inhibit neurokinin 1 receptor desensitization. The protein kinase inhibitors Ro 31-8220, staurosporine, and Zn²⁺ had no effect on neurokinin 1 receptor desensitization, indicating that the kinases affected by these agents are not rate-limiting in neurokinin 1 receptor desensitization in this system.     

Effect of neurotensin on pancreatic function in man

The effect of neurotensin on submaximally-stimulated hepatobiliary and pancreatic secretion was studied in 6 healthy subjects. An intravenous infusion of neurotensin 1.4 ± 0.3 pmol/kg/min, designed to reproduce plasma neurotensin immunoreactivity levels within the physiological range, produced a significant increase in pancreatic bicarbonate output. Plasma concentrations of pancreatic polypeptide rose by 83 ± 16 pmol/l and were associated with a small reduction in trypsin, but no significant change in bilirubin outputs.     

Surfactant Protein A Binds Flagellin Enhancing Phagocytosis and IL-1β Production

Surfactant protein A (SP-A), a pulmonary collectin, plays a role in lung innate immune host defense. In this study the role of SP-A in regulating the inflammatory response to the flagella of Pseudomonas aeruginosa (PA) was examined. Intra-tracheal infection of SP-A deficient (SP-A-/-) C57BL/6 mice with wild type flagellated PA (PAK) resulted in an increase in inflammatory cell recruitment and increase in pro-inflammatory cytokines IL-6 and TNF-α, which was not observed with a mutant pseudomonas lacking flagella (fliC). SP-A directly bound flagellin, via the N-linked carbohydrate moieties and collagen-like domain, in a concentration dependent manner and enhanced macrophage phagocytosis of flagellin and wild type PAK. IL-1β was reduced in the lungs of SP-A-/- mice following PAK infection. MH-s cells, a macrophage cell line, generated greater IL-1β when stimulated with flagellin and SP-A. Historically flagella stimulate IL-1β production through the toll-like receptor 5 (TLR-5) pathway and through a caspase-1 activating inflammasome pathway. IL-1β expression became non-detectable in SP-A and flagellin stimulated MH-s cells in which caspase-1 was silenced, suggesting SP-A induction of IL-1β appears to be occurring through the inflammasome pathway. SP-A plays an important role in the pathogenesis of PA infection in the lung by binding flagellin, enhancing its phagocytosis and modifying the macrophage inflammatory response.     

Effect of Metalaxyl on the incidence and severity of Pearl millet downy mildew disease in Northern Nigeria

Pearl millet downy mildew (DM) incidence, severity and yield losses of two pearl millet varieties (local and improved) due to the disease were determined in the field. Significant differences in the disease incidence and severity were recorded in the plots sown with metalaxyl-treated seeds and those sown with non-treated seeds, indicating the efficacy of the fungicide on the fungus. Yield losses due to non-treatment of seeds with metalaxyl was 40.88 and 45.39% in a local variety and 43.00 and 18.60% in an improved variety in the 2000 and 2001 cropping seasons respectively. Significant differences between plots sown with metalaxyl-treated and those sown with non-treated seeds were obtained for other yield components such as 1000-grains weight, panicle length and weight.